Valve and gas control device

ABSTRACT

A valve includes: a first plate having a first vent hole; a second plate having a second vent hole; a valve chamber positioned between the first plate and the second plate; a valve body including a third vent hole; an exhaust path-forming plate forming a first flow path between the exhaust path-forming plate and the valve body, forming a second flow path between the exhaust path-forming plate and the second plate, and having a fourth vent hole through which the first flow path is in communication with the second flow path; and a fifth vent hole. The first flow path establishes communication between the second vent hole and the fourth vent hole, and the second flow path establishes communication between the fourth vent hole and the fifth vent hole.

CROSS REFERENCE TO RELATED APPLICATION

This is a continuation of U.S. application Ser. No. 17/176,343 filed onFeb. 16, 2021, which is a continuation of International Application No.PCT/JP2019/037182 filed on Sep. 24, 2019 which claims priority fromJapanese Patent Application No. 2018-198385 filed on Oct. 22, 2018. Thecontents of these applications are incorporated herein by reference intheir entireties.

BACKGROUND OF THE DISCLOSURE Field of the Disclosure

The present disclosure relates a valve for regulating gas flow and a gascontrol device including the valve.

Description of the Related Art

There have been proposed various gas control devices for controlling gasflow. For example, Patent Document 1 discloses a gas control deviceincluding a piezoelectric pump, a valve, and a cuff. A diaphragm in thevalve functions as a check valve so as to come into contact with orseparate from a valve seat. The diaphragm in the valve functions as anexhaust valve so as to come into contact with or separate from anopening through which a second valve chamber is in communication with anexhaust path.

-   Patent Document 1: International Publication No. WO 2018/021099

BRIEF SUMMARY OF THE DISCLOSURE

However, the exhaust of air from an existing valve causes sounding. Thesounding occurs as a result of gas flow between the diaphragm and theopening when the diaphragm undergoes transition from the state ofsealing the opening in communication with the exhaust path into thestate of separating from the opening. In the case of using the gascontrol device in a quiet environment, this sounding is heard as noisefor users and annoys them.

An object of the present disclosure is to provide a valve and a gascontrol device that cause less sounding when gas is exhausted.

To achieve the above object, a valve according to an aspect of thepresent disclosure includes: a first plate having a first vent hole; asecond plate positioned to face a main surface of the first plate andhaving a second vent hole; a valve chamber positioned between the firstplate and the second plate; a valve body positioned between the firstplate and the second plate and having a third vent hole, the valve bodycausing the first vent hole and the second vent hole not to be incommunication with each other when a periphery of the third vent hole isin contact with the first plate or the second plate, and causing thefirst vent hole and the second vent hole to be in communication witheach other when the periphery of the third vent hole is separated fromthe first plate and the second plate; an exhaust path-forming platepositioned between the second plate and the valve body, forming a firstflow path between the exhaust path-forming plate and the valve body,forming a second flow path between the exhaust path-forming plate andthe second plate, and having a fourth vent hole through which the firstflow path is in communication with the second flow path; and a fifthvent hole positioned between the first plate and the exhaustpath-forming plate or between the exhaust path-forming plate and thesecond plate. The first flow path establishes communication between thesecond vent hole and the fourth vent hole, and the second flow pathestablishes communication between the fourth vent hole and the fifthvent hole. The valve body causes the first flow path and the second flowpath not to be in communication with each other when the valve body isin contact with a periphery of the fourth vent hole, and the valve bodycauses the first flow path and the second flow path to be incommunication with each other when the valve body is separated from theperiphery of the fourth vent hole. The minimum cross-sectional area ofthe second flow path or the cross-sectional area of the fifth vent holeis smaller than the cross-sectional area of the opening of the fourthvent hole. The direction in which the fourth vent hole extends differsfrom the direction in which the second flow path extends.

A gas control device according to an aspect of the present disclosureincludes: the valve described above; a pump connected to the valvechamber; and a container connected to the first flow path.

A valve according to the present disclosure can provide a valve and agas control device that cause less sounding when gas is exhausted.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

FIG. 1 is a cross-sectional view of a main part of a gas control devicein a first embodiment.

FIG. 2 is an exploded perspective view of a pump and a valve in thefirst embodiment.

FIG. 3 is a perspective view as viewed from the longitudinal section ofthe valve.

FIG. 4 is a bottom view of a case.

FIG. 5 is a longitudinal sectional view of the valve.

FIG. 6 is a perspective view of a first plate as viewed from the cuff.

FIG. 7 is a perspective view of the first plate as viewed from the pump.

FIG. 8 is a view for describing air flow in the gas control deviceduring driving of the pump.

FIG. 9 is a view for describing air flow in the gas control device afterthe driving of the pump is stopped.

FIG. 10 is a plan view of a flow path-forming plate in a modification ofthe first embodiment.

FIG. 11 is a view for describing a modification of a communication hole.

FIG. 12 is a view for describing a modification of the communicationhole.

FIG. 13 is a plan view of a flow path-forming plate in a modification ofthe first embodiment.

FIG. 14 is a longitudinal sectional view of the case and the surroundingarea in a modification of the first embodiment.

FIG. 15 is a longitudinal sectional view of the case and the surroundingarea in a modification of the first embodiment.

FIG. 16 is a longitudinal sectional view of the case and the surroundingarea in a modification of the first embodiment.

FIG. 17 is a plan view of a flow path-forming plate in a modification ofthe first embodiment.

FIG. 18 is a plan view of a flow path-forming plate in a modification ofthe first embodiment.

FIG. 19 is a longitudinal sectional view of the case and the surroundingarea in a modification of the first embodiment.

FIG. 20 is a plan view of a flow path-forming plate in a modification ofthe first embodiment.

FIG. 21 is a longitudinal sectional view of a case and the surroundingarea in a modification of the first embodiment.

FIG. 22 is a longitudinal sectional view of a case and the surroundingarea in a modification of the first embodiment.

FIG. 23 is a view for describing the connection part between the valveand the cuff in the embodiment.

FIG. 24 is a view for describing a modification of the connection partbetween the valve and the cuff.

FIG. 25 is a plan view of a flow path-forming plate in a modification ofthe first embodiment.

DETAILED DESCRIPTION OF THE DISCLOSURE

A valve according to an aspect of the present disclosure includes: afirst plate having a first vent hole; a second plate positioned to facea main surface of the first plate and having a second vent hole; a valvechamber positioned between the first plate and the second plate; a valvebody positioned between the first plate and the second plate and havinga third vent hole, the valve body causing the first vent hole and thesecond vent hole not to be in communication with each other when aperiphery of the third vent hole is in contact with the first plate andthe second plate, and causing the first vent hole and the second venthole to be in communication with each other when the periphery of thethird vent hole is separated from the first plate and the second plate;an exhaust path-forming plate positioned between the second plate andthe valve body, forming a first flow path between the exhaustpath-forming plate and the valve body, forming a second flow pathbetween the exhaust path-forming plate and the second plate, and havinga fourth vent hole through which the first flow path is in communicationwith the second flow path; and a fifth vent hole positioned between thefirst plate and the exhaust path-forming plate or between the exhaustpath-forming plate and the second plate. The first flow path establishescommunication between the second vent hole and the fourth vent hole, andthe second flow path establishes communication between the fourth venthole and the fifth vent hole. The valve body causes the first flow pathand the second flow path not to be in communication with each other whenthe valve body is in contact with a periphery of the fourth vent hole,and the valve body causes the first flow path and the second flow pathto be in communication with each other when the valve body is separatedfrom the periphery of the fourth vent hole. The minimum cross-sectionalarea of the second flow path or the cross-sectional area of the fifthvent hole is smaller than the cross-sectional area of the opening of thefourth vent hole. The direction in which the fourth vent hole extendsdiffers from the direction in which the second flow path extends.

According to this configuration, in the exhaust path from the containerto the fifth vent hole, the minimum cross-sectional area of the secondflow path or the cross-sectional area of the fifth vent hole is smallerthan the cross-sectional area of the fourth vent hole through which thefirst flow path is in communication with the second flow path.Therefore, the flow rate of gas exhausted through the fifth vent hole isthe highest in a region having the minimum cross-sectional area of thesecond flow path or at the fifth vent hole, and the flow rate of gaspassing through the fourth vent hole can be reduced. This results in alow flow rate of gas flowing through the gap between the valve body andthe fourth vent hole that start to separate from each other when gas isexhausted and results in less sounding at this gap. Even if the valvebody enters the fourth vent hole, the valve body is unlikely to extendto the second flow path because the direction in which the fourth venthole extends differs from the direction in which the second flow pathextends. This configuration enables the valve body to move smoothly whengas is exhausted.

The minimum cross-sectional area of the second flow path may be smallerthan the cross-sectional area of the opening of the fifth vent hole.According to this configuration, sounding occurs not in the fifth venthole but in the second flow path. Since the direction in which thefourth vent hole extends differs from the direction in which the secondflow path extends, sounds generated in the second flow path easilyreflect inside, and sounds are unlikely to come out through the fifthvent hole. This configuration can reduce noise.

The second flow path may have a narrowing part. According to thisconfiguration, the exhaust time can easily be designed because theexhaust time can be adjusted by the size of the cross-sectional area ofa flow path formed by the narrowing part.

The valve may have multiple fifth vent holes. This configuration canprevent abnormal deformation of the valve body and can further preventinhibition of pump vibration.

The valve may have multiple second flow paths. Since multiple secondflow paths are provided, the flow rate in each second flow path can bereduced, and the fourth vent hole may have a smaller size.

The second plate may be part of a case that accommodates the valve.According to this configuration, the height of the valve can be reduced.

The first plate may have a groove around the first vent hole. When, forexample, an adhesive is used for bonding between the first plate and theexhaust path-forming plate, an excess amount of the adhesive flows intothe groove. This configuration can prevent the adhesive from interferingwith the valve operation and the pump operation.

The first plate may have multiple first vent holes. This configurationcan prevent abnormal deformation of a diaphragm 120 and can furtherprevent inhibition of vibration of a pump connected to the valve.

A gas control device may be configured to include the valve describedabove, a pump connected to the valve chamber, and a container connectedto the first flow path. According to this configuration, the gas controldevice causes less sounding when gas is exhausted.

The valve and the gas control device according to the present disclosurewill be described below with reference to the drawings. In the drawings,members having substantially the same function and the sameconfiguration are denoted by the same reference characters, and thedescription of the members may be omitted herein. For easyunderstanding, the components are mainly and schematically illustratedin the drawings.

The embodiment described below is a specific example of the presentdisclosure, and the present disclosure is not limited to theconfiguration of the embodiment. The values, shapes, configurations,steps, sequence of steps, and the like specifically described in thefollowing embodiment are illustrative only and are not construed aslimiting the present disclosure. Among the components in the followingembodiment, components that are not mentioned in independent claimsindicating the broadest concept are described as optional components.This applies to the configurations described in modifications of theembodiment, and the configurations described in the modifications may becombined.

First Embodiment

First, a gas control device will be described with reference to FIG. 1to FIG. 3. FIG. 1 is a cross-sectional view of a main part of a gascontrol device 100 in a first embodiment. FIG. 2 is an explodedperspective view of a pump 10 and a valve 101 in the first embodiment.FIG. 3 is a perspective view as viewed from the longitudinal section ofthe valve 101. The X-axis direction indicates the direction in which acheck valve 160 and an exhaust valve 170 are arranged. The Z-axisdirection indicates the stacking direction (height direction) of membersthat constitute the pump 10 and the valve 101. The Y-axis directionindicates the direction perpendicular to the Z-axis direction and theX-axis direction.

1. Gas Control Device

The gas control device 100 includes the pump 10, the valve 101, a cuff109, and a controller 115. The gas control device 100 is provided in,for example, a sphygmomanometer for measuring the blood pressure of asubject.

The valve 101 has a first plate 191 having first vent holes 111 and acase 190. The case 190 has a second plate 192 having second vent holes112 and an exhaust path-forming plate 193 forming an exhaust hole 113and a second flow path 133 between the exhaust path-forming plate andthe second plate 192. The exhaust hole 113 serves as a fifth vent hole.

The valve 101 includes the check valve 160 and the exhaust valve 170.The valve 101 is connected to the cuff 109 such that a manchette rubbertube 109 a of the cuff 109 is joined to the area around the second ventholes 112 of the second plate 192 by using, for example, an adhesive.The connection between the manchette rubber tube 109 a and the secondplate 192 may be performed by using a double-sided tape or an adhesivetape instead of using an adhesive. The exhaust hole 113 is opened to theatmosphere. The cuff 109 corresponds to an example of the “container” inthe present disclosure.

The pump 10 has a pump housing 80 connected to the first vent hole. Theupper surface of the pump housing 80 is joined to the bottom surface ofthe first plate 191 of the valve 101.

The controller 115 includes, for example, a microcomputer, a CPU, or aFGPA, and controls the operation of each component of the gas controldevice 100. The controller 115 is connected to the pump 10 and sendscontrol signals to the pump 10. The controller 115 generates an AC drivevoltage from a power supply and applies the AC drive voltage to the pump10 through a power feed plate 70 to drive the pump 10. The controller115 then measures the blood pressure on the basis of the pressure of theair stored in the cuff 109. The pressure of the air stored in the cuff109 is detected by a pressure sensor (not shown) and inputted to thecontroller 115.

2. Structure of Pump

Next, the structure of the pump 10 will be described. Since the pump 10has a similar structure to existing pumps, a brief overview of the pump10 will be provided, and a detail description will be omitted.

The pump 10 includes a substrate 91, a flow path-forming plate 50, aflexible plate 51, a vibration plate unit 60, a piezoelectric actuator40, a spacer 53, and the power feed plate 70, which are stacked in thisorder. The substrate 91, the flexible plate 51, a part of the vibrationplate unit 60, the spacer 53, and the power feed plate 70 form the pumphousing 80. The inner space of the pump housing 80 corresponds to a pumpchamber 45.

A vibration plate 41 is flexibly and elastically supported to a frameplate 61 at three points with joints 62. A piezoelectric element 42 isdisposed on the upper surface of the vibration plate 41 having a discshape. The vibration plate 41 and the piezoelectric element 42 form thepiezoelectric actuator 40 having a disc shape.

The spacer 53 made of resin is disposed on the upper surface of theframe plate 61. The spacer 53 electrically insulates the power feedplate 70 and the vibration plate unit 60 from each other.

The power feed plate 70 made of metal is disposed on the upper surfaceof the spacer 53. The power feed plate 70 has a frame section 71 havinga substantially circular opening, an internal terminal 73 protrudinginward inside the opening, and an external terminal 72 protrudingoutward. An end portion of the internal terminal 73 is joined to thesurface of the piezoelectric element 42 by soldering. The upper surfaceof the power feed plate 70 is in contact with the lower surface of thevalve 101.

The flexible plate 51 is disposed on the lower surface of the frameplate 61. The flexible plate 51 has a suction hole 52 at a centralportion. The flexible plate 51 includes a fixed portion 57 and a movableportion 58. The fixed portion 57 is fixed to the substrate 91. Themovable portion 58 is positioned nearer to the center than the fixedportion 57 and faces cavities 92. The flow path-forming plate 50 isdisposed on the lower surface of the flexible plate 51.

The flow path-forming plate 50 has a columnar cavity 50 a at a centralportion. Linear flow paths 50 b are formed radially and outward from thecavities 50 a. End portions of the flow paths 50 b are in communicationwith the cavities 92 of the substrate 91.

When the controller 115 applies an AC drive voltage to the externalterminal 72 and the terminal of the flexible plate 51, the piezoelectricactuator 40 undergoes concentric flexural vibration. Furthermore, thevibration of the piezoelectric actuator 40 causes the movable portion 58of the flexible plate 51 to vibrate. According to this configuration,the pump 10 causes air to be sucked into the pump chamber 45 through thecavities 92, which are in communication with outside, the flow paths 50b, which are in communication with the cavities 92, and the suction hole52. Furthermore, the pump 10 discharges the air from the pump chamber 45into the inside of the valve 101 through the first vent holes 111. Thesuction hole 52 is always in communication with the first vent holes111.

3. Structure of Valve

As illustrated in FIG. 1 to FIG. 3, the valve 101 includes the firstplate 191, a frame member 195, the diaphragm 120 formed of an ellipticalthin film, a seal member 152 formed of an elliptical thin film, theexhaust path-forming plate 193, and the second plate 192, which arestacked in this order. According to this configuration, a first flowpath 114 is formed by the inner surface of the second plate 192, theexhaust path-forming plate 193, and the diaphragm 120. The second plate192 is positioned to face a main surface 191 g of the first plate 191.The diaphragm 120 and the seal member 152 are provided in an openingregion of the frame member 195. The valve 101 includes a valve chamber131 between the first plate 191 and the second plate 192.

The frame member 195 may have a plate shape or a sheet shape. Examplesof the frame member 195 having a sheet shape include an adhesive layer,such as a double-sided tape.

The exhaust path-forming plate 193 has a protrusion 193 a partiallyprotruding outward. The second plate 192 also has a protrusion 192 apartially protruding outward. The exhaust path-forming plate 193 and theframe member 195 are stacked on top of each other such that the outersurface of the exhaust path-forming plate 193 is flush with the outersurface of the frame member 195, excluding the protrusions 193 a and 192a.

The outer surface of the exhaust path-forming plate 193 may not be flushwith the outer surface of the frame member 195. The outer surfaces ofthe exhaust path-forming plate 193 and the frame member 195 may form,for example, a stepped surface.

The second vent holes 112 are through-holes in the second plate 192. Theopening face of the second vent holes 112 is thus flush with orsubstantially flush with the outer surface of the second plate 192.

The exhaust path-forming plate 193 is positioned between the secondplate 192 and the diaphragm 120 in the stacking direction. The exhaustpath-forming plate 193 forms the first flow path 114 together with thesecond plate 192 and the diaphragm 120. The first flow path 114 ispositioned between the exhaust path-forming plate 193 and the diaphragm120. The exhaust path-forming plate 193 forms the second flow pathbetween the exhaust path-forming plate 193 and the second plate 192. Theexhaust path-forming plate 193 includes a communication hole 134 throughwhich the first flow path 114 is in communication with the second flowpath 133. The communication hole 134 serves as the fourth vent hole. Oneend portion of the first flow path 114 is in communication with thesecond vent holes 112 in the second plate. The other end portion of thefirst flow path 114 is in communication with the second flow path 133through the communication hole 134. The opening of the second flow path133 adjacent to the second plate 192 is covered with the second plate192. In this embodiment, the direction in which the communication hole134 differs from the direction in which the second flow path 133extends. These directions cross each other, for example, at rightangles, but the directions do not necessarily cross each other at rightangles. The directions may cross each other at oblique angles.

Since the exhaust path-forming plate 193 and the second plate 192 arearranged to satisfy the above relationship, the opening of the secondflow path 133 adjacent to the frame member 195 except for one endportion and the other end portion is covered with the exhaustpath-forming plate 193. Therefore, one end portion of the second flowpath 133 formed in the exhaust path-forming plate 193 is opened towardthe frame member 195. This cavity is the exhaust hole 113 serving as thefifth vent hole. The exhaust hole 113 is provided between the exhaustpath-forming plate 193 and the second plate 192. The second flow path133 establishes communication between the communication hole 134 and theexhaust hole 113. The exhaust hole 113 may be provided between theexhaust path-forming plate 193 and the first plate 191 such that theprotrusion 193 a of the exhaust path-forming plate 193 extends towardthe first plate 191 (in the negative Z-axis direction).

The communication hole 134 is provided in the other end portion of thesecond flow path 133 that faces the exhaust path-forming plate 193, andthe communication hole 134 at the other end portion is in communicationwith the first flow path 114. The first flow path 114 is partiallyformed by one main surface of the second plate 192 whose the other mainsurface forms the top surface of the valve 101. Therefore, the valve 101can be made thinner while the first flow path 114 is formed in thein-plane direction.

The frame member 195 forms the inner space of the valve 101 togetherwith the exhaust path-forming plate 193, the second plate 192, and thefirst plate 191. The diaphragm 120 is disposed in the inner space of thevalve 101. The diaphragm 120 is an example of the “valve body” in thepresent disclosure.

The first plate 191 and the case 190 are made of, for example, metal,resin, or a mixture of these. Joining between the second plate 192, theexhaust path-forming plate 193, the frame member 195, and the firstplate 191 is performed by using, for example, a double-sided tape,thermal diffusion bonding, or an adhesive.

As illustrated in FIG. 1 and FIG. 3, the second plate 192 has multiplesecond vent holes 112, which are in communication with the cuff 109. Thesecond plate 192 is made of, for example, metal or resin.

As illustrated in FIG. 1 and FIG. 3, the first plate 191 has first ventholes 111, which are in communication with the pump 10. The first plate191 is made of, for example, metal and formed by half etching. The firstplate 191 has a valve seat 138 protruding toward the cuff 109.

As illustrated in FIG. 1 and FIG. 2, the diaphragm 120 has a circularhole 121 at a central portion of a region that faces the valve seat 138.The hole 121 serves as the third vent hole. The diameter of the hole 121is smaller than the diameter of a face of the valve seat 138 that comesinto contact with the diaphragm 120. The perimeter of the diaphragm 120is smaller than the perimeters of the first plate 191 and the secondplate 192. The diaphragm 120 is made of rubber, such as EPDM (ethylenepropylene rubber) or silicone.

The diaphragm 120 is sandwiched between the first plate 191 and theexhaust path-forming plate 193 with the seal member 152 interposedbetween the diaphragm 120 and the exhaust path-forming plate 193.According to this configuration, a part of the diaphragm 120 can comeinto contact with the communication hole 134 of the exhaust path-formingplate 193, and the periphery of the hole 121 in the diaphragm 120 cancome into contact with the valve seat 138. The valve seat 138 isprovided in the first plate 191 so as to press the area around the hole121 in the diaphragm 120. The valve seat 138 is made of, for example,metal.

The diaphragm 120 divides the inner space defined by the second plate192, the first plate 191, and the frame member 195. A portion of theinner space that is adjacent to the first plate 191 is the valve chamber(first chamber) 131, while a portion of the inner space that is adjacentto the second plate 192 is the first flow path (second chamber) 114. Thediameter of a face of the valve seat 138 that comes into contact withthe diaphragm 120 is, for example, 1.5 mm.

In the valve 101, a part of the seal member 152 is positioned in a firstflow path 114. The seal member 152 is formed of, for example, adouble-sided tape or an adhesive.

Next, the check valve 160 and the exhaust valve 170 in the valve 101will be described.

The check valve 160 includes the periphery of the hole 121 in thediaphragm 120, and the valve seat 138 which comes into contact with theperiphery of the hole 121 to cover the hole 121. In the check valve 160,the diaphragm 120 comes into contact with or separates from the valveseat 138 on the basis of the pressure of the valve chamber 131 and thepressure of the first flow path 114. The diaphragm 120 causes the firstvent holes 111 and the second vent holes 112 not to be in communicationwith each other when the periphery of the hole 121 of the diaphragm 120is in contact with the first plate 191. The diaphragm 120 causes thefirst vent holes 111 and the second vent holes 112 to be incommunication with each other when the periphery of the hole 121 of thediaphragm 120 is separated from the first plate 191.

Next, the exhaust valve 170 includes a part of the diaphragm 120, and aperipheral area of a cavity 134 a of the communication hole 134 thatfaces the diaphragm 120. In the exhaust valve 170, a part of thediaphragm 120 comes into contact with or separates from the peripheralarea of the cavity 134 a of the communication hole 134 on the basis ofthe pressure of the valve chamber 131 and the pressure of the first flowpath 114.

Next, the first plate 191 will be described in detail with reference toFIG. 6 and FIG. 7. FIG. 6 is a perspective view of the first plate asviewed from the cuff 109. FIG. 7 is a perspective view of the firstplate as viewed from the pump 10. The first plate 191 has grooves 191 a,191 b, and 191 c for receiving excess adhesive used for bonding betweenthe first plate 191 and the case 190. The adhesive is applied betweenthe frame member 195 and the diaphragm 120 and strongly bonds the firstplate 191 and the case 190. The adhesive is, for example, a siliconeadhesive. The grooves 191 a, 191 b, and 191 c are formed around thefirst vent holes 111. On the side of the first plate 191 adjacent to thecuff 109, the groove 191 a is formed so as to surround the outer side ofthe first vent holes 111. On the side of the first plate 191 adjacent tothe pump 10, the groove 191 b having an arc shape and the groove 191 chaving a semicircle shape are formed nearer to the center than thegroove 191 a. The grooves 191 a, 191 b, and 191 c can prevent excessadhesive from leaking from the first plate 191. When a buffer for theadhesive is thus provided in a valve storage, the adhesive flows intothe buffer, which can prevent the adhesive from interfering with thevalve operation and the pump operation.

The central side of the groove 191 c is exposed to an opening 191 d. Theopening 191 d is a through-hole in order to avoid the contact to thepower feed terminal of the power feed plate 70. The first plate 191 hasa wall portion 191 e at the periphery of the first plate 191. The wallportion 191 e extends toward the pump 10. The wall portion 191 e hasmultiple recesses 191 f, which are recessed toward the cuff 109. Therecesses 191 f reduce the transmission of the vibration of the vibrationplate unit 60. In addition, the formation of the first vent holes 111can prevent abnormal deformation of the diaphragm 120 and can furtherprevent inhibition of pump vibration.

Next, the operation of the gas control device 100 when it is used forblood pressure measurement will be described.

FIG. 8 is a view for describing air flow in the gas control device 100during driving of the pump 10 illustrated in FIG. 1. The controller 115turns on the pump 10 when blood pressure measurement is started. Whenthe pump 10 is driven, first, air flows into the pump chamber 45 in thepump 10 through the cavities 92 and the suction hole 52. Next, the airis discharged through the first vent holes 111 and flows into the valvechamber 131 of the valve 101.

In the exhaust valve 170, the pressure of the valve chamber 131 thusbecomes higher than the pressure of the first flow path 114. Asillustrated in FIG. 8, the diaphragm 120 seals the communication hole134 to block connection between the second vent holes 112 and the secondflow path 133.

In the check valve 160, the pressure of the valve chamber 131 becomeshigher than the pressure of the first flow path 114. The area around thehole 121 in the diaphragm 120 thus separates from the valve seat 138, sothat the first vent holes 111 are connected to the second vent holes 112through the hole 121.

As a result, the air is delivered to the cuff 109 from the pump 10through the first vent holes 111, the hole 121, and the second ventholes 112 of the valve 101, so that the pressure (air pressure) in thecuff 109 increases. The diaphragm 120 may abut the second plate 192 as aresult of large deformation of the diaphragm 120.

The diaphragm 120 is fixed to the exhaust path-forming plate 193 and thefirst plate 191 such that the periphery of the hole 121 of the diaphragm120 is in contact with the valve seat 138. The valve seat 138 pressesthe area around the hole 121 in the diaphragm 120.

The air flowing out through the hole 121 via the first vent holes 111 ofthe valve 101 thus has a slightly lower pressure than the dischargepressure of the pump 10 and flows into the first flow path 114 throughthe hole 121. The valve chamber 131 receives the discharge pressure ofthe pump 10.

As a result, in the valve 101, the pressure of the valve chamber 131 isslightly higher than the pressure of the first flow path 114, and thediaphragm 120 seals the communication hole 134 and maintains the hole121 open.

FIG. 9 is a view for describing air flow in the gas control device 100after the driving of the pump 10 illustrated in FIG. 1 is stopped. Thecontroller 115 turns off the pump 10 when blood pressure measurement isended. When the driving of the pump 10 is stopped, the air in the pumpchamber 45 and the valve chamber 131 is readily exhausted to the outsideof the gas control device 100 through the suction hole 52 and thecavities 92 of the pump 10. The pressure of the cuff 109 is applied tothe first flow path 114 through the second vent holes 112.

As a result, in the check valve 160, the pressure of the valve chamber131 becomes lower than the pressure of the first flow path 114. Thediaphragm 120 comes into contact with the valve seat 138 to seal thehole 121. In the exhaust valve 170, the pressure of the valve chamber131 becomes lower than the pressure of the first flow path 114. Thediaphragm 120 separates from the cavity 134 a of the communication hole134 and opens the second flow path 133. In other words, in the valve101, the second vent holes 112 are connected to the second flow path 133through the first flow path 114 and the communication hole 134.

Since the exhaust hole 113 is opened toward the pump housing 80 asdescribed above, the air in the cuff 109 is readily discharged from theexhaust hole 113 toward the pump housing 80 via the second vent holes112, the first flow path 114, the communication hole 134, and the secondflow path 133.

As described above, the valve 101 includes: the first plate 191 havingthe first vent holes 111; the second plate 192 positioned to face themain surface of the first plate 191 and having the second vent holes112; the valve chamber 131 positioned between the first plate 191 andthe second plate 192; and the hole 121 positioned between the firstplate 191 and the second plate 192 and serving as the third vent hole.The valve 101 further includes: the diaphragm 120, which serves as thevalve body, causing the first vent holes 111 and the second vent holes112 not to be in communication with each other when the periphery of thehole 121 is in contact with the first plate 191 and the second plate192, and causing the first vent holes 111 and the second vent holes 112to be in communication with each other when the periphery of the hole121 is separated from the first plate 191 and the second plate 192; theexhaust path-forming plate 193 positioned between the second plate 192and the diaphragm 120, forming the first flow path 114 between theexhaust path-forming plate 193 and the diaphragm 120, forming the secondflow path 133 between the exhaust path-forming plate 193 and the secondplate 192, and having the communication hole 134, which serves as thefourth vent hole, through which the first flow path 114 is incommunication with the second flow path 133; and the exhaust hole 113,which serves as the fifth vent hole, between the first plate 191 and theexhaust path-forming plate 193 or between the exhaust path-forming plate193 and the second plate 192. The first flow path 114 establishescommunication between the second vent holes 112 and the communicationhole 134, and the second flow path 133 establishes communication betweenthe communication hole 134 and the exhaust hole 113. The diaphragm 120causes the first flow path 114 and the second flow path 133 not to be incommunication with each other when the diaphragm 120 is in contact withthe periphery of the communication hole 134, and causes the first flowpath 114 and the second flow path 133 to be in communication with eachother when the diaphragm 120 is separated from the periphery of thecommunication hole 134. The minimum cross-sectional area Cs2 of thesecond flow path 133 or the cross-sectional area of the exhaust hole 113is smaller than the cross-sectional area Cs1 of the opening of thecommunication hole 134. The direction in which the communication hole134 extends differs from the direction in which the second flow path 133extends. According to this configuration, in the exhaust path from thecuff 109 to the exhaust hole 113, the minimum cross-sectional area Cs2of the second flow path 133 or the cross-sectional area of the exhausthole 113 is smaller than the cross-sectional area Cs1 of thecommunication hole 134 through which the first flow path 114 is incommunication with the second flow path 133. Therefore, the flow rate ofgas being exhausted is the highest at the minimum cross-sectional areaCs2 of the second flow path 133 or at the exhaust hole 113, and the flowrate of gas passing through the communication hole 134 can be reduced.This results in a low flow rate of gas flowing through the gap betweenthe diaphragm 120 and the communication hole 134 that start to separatefrom each other when gas is exhausted and results in less sounding atthis gap. Even if the diaphragm 120 enters the communication hole 134,the diaphragm 120 is unlikely to extend to the second flow path 133because the direction in which the communication hole 134 extendsdiffers from the direction in which the second flow path 133 extends.This configuration enables the diaphragm 120 to move smoothly when gasis exhausted.

Since the exhaust time depends on the minimum cross-sectional area Cs2of the second flow path 133 or the cross-sectional area of the exhausthole 113, the cross-sectional area Cs1 of the communication hole 134 canbe larger than that in the related art. The communication hole 134having a large cross-sectional area Cs1 can lower the flow rate of theair flowing near the cavity 134 a when the diaphragm 120 separates fromthe communication hole 134. The flow rate of gas passing through thecommunication hole 134 can be reduced by making the minimumcross-sectional area Cs2 of the second flow path 133 or thecross-sectional area of the exhaust hole 113 smaller than thecross-sectional area of the communication hole 134. This configurationcan prevent the diaphragm 120 from being brought closer to thecommunication hole 134 again. This results in less vibration of thediaphragm 120 when gas is exhausted and results in low noise generatedin the cavity 134 a of the communication hole 134 due to vibration ofthe diaphragm 120.

The cross-sectional area Cs1 of the communication hole 134 is the areain the direction perpendicular or substantially perpendicular to thedirection from the main surface of the first plate 191 to the mainsurface of the second plate 192. The cross-sectional area Cs2 of thesecond flow path 133 is the area of the cross-section of the flow pathas viewed in the direction from the main surface of the first plate 191to the main surface of the second plate 192.

The minimum cross-sectional area Cs2 of the second flow path 133 issmaller than the cross-sectional area of the exhaust hole 113. Thisconfiguration can reduce jet noise. Since the direction in which thecommunication hole 134 extends differs from the direction in which thesecond flow path 133 extends, sounds generated in the second flow path133 easily reflect inside the valve 101, and sounds are unlikely to comeout through the exhaust hole 113. This configuration can reduce noise.

The first vent holes 111 of the first plate 191 can prevent abnormaldeformation of the diaphragm 120 and can further prevent inhibition ofpump vibration.

(Modification 1)

Next, a valve according to a modification of the first embodiment willbe described with reference to FIG. 10 to FIG. 12. FIG. 10 is aschematic plan view of a second flow path 133 of an exhaust path-formingplate 193A and the surrounding area in Modification 1. FIG. 11 and FIG.12 are schematic plan views of communication holes 134B and 134C inModification 1.

The transverse section of the communication hole 134 formed in theexhaust path-forming plate 193 is not necessarily circle. For example,as illustrated in FIG. 10, the transverse section of the communicationhole 134 may be square, rectangle, or rectangle including these shapes.The transverse section of the communication hole 134 may be, forexample, triangle, polygon, star, or hexagram, in addition to rectangle.

The transverse section of the communication hole 134 may have a ringshape with no through-hole at the center. As illustrated in FIG. 11, thetransverse section of the communication hole 134B may have a C-shapewith no through-hole at the center. As illustrated in FIG. 12, thetransverse section of the communication hole 134C may have a segmentedring shape with no through-hole at the center.

(Modification 2)

Next, a valve according to a modification of the first embodiment willbe described with reference to FIG. 13. FIG. 13 is a schematic plan viewof a second flow path 133 of an exhaust path-forming plate 193B and thesurrounding area in Modification 2. In Modification 2, the second flowpath 133A has a narrowing part 136 having a cross-sectional area Cs3smaller than the cross-sectional area of the communication hole 134.When the second flow path 133A has the narrowing part 136, the minimumcross-sectional area Cs2 of the second flow path 133A corresponds to thecross-sectional area Cs3 of the narrowing part 136. Therefore, thecross-sectional area of the second flow path 133A excluding thenarrowing part 136 may be larger than the cross-sectional area Cs1 ofthe communication hole 134. This configuration improves the freedom ofdesign of the communication hole 134 and the second flow path 133A. Inaddition, the exhaust time can easily be designed because the exhausttime can be adjusted by the size of the cross-sectional area Cs3 of aflow path formed by the narrowing part 136.

The flow path formed by the narrowing part 136 is, for example, a narrowflow path in the second flow path 133A that is distant from the innerwall of the exhaust path-forming plate 193B. The narrowing part 136 mayhave, for example, a wall 136 a extending toward the flow path centerfrom the inner wall of the exhaust path-forming plate 193B and a wall136 b or pipe with the cross-sectional area Cs3 connected to the wall136 a and extending in the longitudinal direction or may simply have awall 136 a having a through-hole with the cross-sectional area Cs3. Thecross-sectional area Cs3 of the narrowing part 136 is smaller than thecross-sectional area Cs1 of the communication hole 134, and Cs1 and Cs3satisfy the relationship of Cs1>Cs3.

In a second flow path 133B, as illustrated in FIG. 14, a narrowing part136A may be disposed below the lower surface of the second plate 192.The narrowing part 136A may be a protrusion protruding from the secondplate 192 toward the diaphragm 120 or a separate resin or metal memberattached to the lower surface of the second plate 192.

The narrowing part 136A makes the minimum cross-sectional area Cs4 ofthe second flow path 133B smaller than the cross-sectional area Cs1 ofthe communication hole 134.

As illustrated in FIG. 15, a narrowing part 136B may be disposed at theboundary between the communication hole 134 and the second flow path133. As illustrated in FIG. 16, a narrowing part 136C may be disposed soas to span the communication hole 134 and the second flow path 133.

(Modification 3)

Next, a valve according to a modification of the first embodiment willbe described with reference to FIG. 17. FIG. 17 is a schematic plan viewof a second flow path 133 of an exhaust path-forming plate 193C and thesurrounding area in Modification 3. In Modification 3, the second flowpath 133 is connected to two exhaust holes 113. In other words, theexhaust path-forming plate 193C has two exhaust holes 113 in aprotrusion 193 a. The holes at multiple sites in this way allow exhaustof air even if one of the holes is closed.

As illustrated in FIG. 18 and FIG. 19, an exhaust path-forming plate193D may have two protrusions 193 a and may have two second flow paths133 connected to the respective exhaust holes 113 each provided in eachprotrusion 193 a. When the valve 101 has two second flow paths 133, thesum of the minimum cross-sectional areas of the second flow paths 133 issmaller than the cross-sectional area of the communication hole 134.

As illustrated in FIG. 20, two exhaust paths each formed by thecommunication hole 134, the second flow path 133, and the exhaust hole113 may be provided. Since the flow rate in each exhaust path can bereduced by providing two exhaust paths, the communication hole 134 mayhave a smaller size.

(Modification 4)

Next, a valve according to a modification of the first embodiment willbe described with reference to FIG. 21. FIG. 21 is a partiallongitudinal sectional view of a valve 101 in Modification 4. InModification 4, an exhaust hole 113A is opened to the outside from asecond flow path 133C and does not face the pump 10. Thus, an exhaustpath-forming plate 193D has no protrusion 193 a. As illustrated in FIG.22, a second plate 192A may have an exhaust hole 113A so that air may beexhausted toward the cuff from a second flow path 133D. Theconfiguration according to Modification 4 facilitates attachment of thevalve 101 when the case 190 is a housing of a device attached to thevalve 101.

Next, the bonding between the valve 101 and the manchette rubber tube109 a of the cuff 109 in the first embodiment will be described withreference to FIG. 23. The valve 101 may be bonded to the manchetterubber tube 109 a, which is an adhesion target, with an adhesivematerial 110 interposed therebetween. The adhesive material 110 is, forexample, a double-sided tape. The manchette rubber tube 109 a and theadhesive material 110 respectively have a hole 109 b and a hole 110 a attheir central portions. The hole 109 b and the hole 110 a are incommunication with the second vent hole 112.

The adhesive material 110 may have a rectangular shape so as to fix fourcorners of the valve 101, but is preferably shaped so as not to fix fourcorners of the valve 101. Examples of the adhesive material shaped so asnot to fix four corners include an adhesive material 110A having apolygonal shape with more vertices than squares, as illustrated in FIG.24, and an adhesive material having a circular shape. The adhesivematerial 110A also has a hole 110Aa at its central portion. The hole110Aa is in communication with the second vent hole 112.

The leakage of vibration of the vibration plate unit 60 transmittedthrough the valve 101 causes the four corners of the valve 101 tovibrate most in the upper surface of the valve 101. When the adhesivematerial 110A is shaped so as not to fix the four corners of the valve101, the vibration transmitted to the adhesion target from the valve 101through the adhesive material 110A can be mitigated. This configurationcan improve pump characteristics.

The present disclosure is not limited to the above embodiment, and theembodiment can be modified in the following manner.

(1) In the above embodiment, air is used as a gas, but gas is notlimited to air. The valve and the gas control device may be used for gasother than air.

(2) In the above embodiment, the frame member 195 is not limited to aplate member and may be a sheet member, such as a double-sided tape.

(3) In Modification 2 of the first embodiment, the second flow path 133Ahas the narrowing part 136, but the form of the narrowing part 136 isnot limited to this. For example, as illustrated in FIG. 25, a part ofthe second flow path 133A may be divided into multiple flow paths bymultiple narrowing parts 136 d. In this case, the minimumcross-sectional area Cs2 of the second flow path 133A is the sum of thecross-sectional areas Cs3 a of the divided flow paths, where thecross-sectional area of each of the divided flow paths is defined as Cs3a. The sum of the cross-sectional areas of the divided flow paths issmaller than the cross-sectional area Cs1 of the communication hole 134.The example of FIG. 25 satisfies the relationship of 4×Cs3 a<Cs1.

In addition to the configuration in which the narrowing parts 136 d eachhaving a rectangular shape are arranged in the second flow path 133,rectangular narrowing parts may be arranged in a staggered manner or acylindrical narrowing part may be disposed in the second flow path 133.

When the valve chamber 131 has one communication hole 134, one secondflow path 133, and two exhaust holes 113 as illustrated in FIG. 17, thecross-sectional area Cs1 of the communication hole 134 is larger thanthe cross-sectional area Cs2 of the second flow path 133 or thecross-sectional area of the exhaust holes 113. When the valve chamber131 has one communication hole 134, multiple second flow paths 133, andmultiple exhaust holes 113 as illustrated in FIG. 18, thecross-sectional area Cs1 of the communication hole 134 is larger thanthe sum of the cross-sectional areas Cs2 of the second flow paths or thesum of the cross-sectional areas of the exhaust holes 113. When thevalve chamber 131 has multiple communication holes 134, multiple secondflow paths 133, and multiple exhaust holes 113 as illustrated in FIG.20, the sum of the cross-sectional areas Cs1 of the communication holes134 is larger than the sum of the cross-sectional areas Cs2 of thesecond flow paths 133 or the sum of the cross-sectional areas of theexhaust holes 113.

The present disclosure can apply to a valve and a gas control deviceincluding the valve.

-   -   10 Pump    -   40 Piezoelectric actuator    -   41 Vibration plate    -   42 Piezoelectric element    -   50 Flow path-forming plate    -   50 a Cavity    -   50 b Flow path    -   51 Flexible plate    -   58 Movable portion    -   60 Vibration plate unit    -   61 Frame plate    -   70 Power feed plate    -   91 Substrate    -   92 Cavity    -   100 Gas control device    -   101 Valve    -   109 Cuff    -   109 a Manchette rubber tube    -   109 b Hole 110, 110 a Adhesive material    -   110 a, 110 aa Hole    -   111 First vent hole    -   112 Second vent hole    -   113, 113 a Exhaust hole    -   114 First flow path    -   115 Controller    -   120 Diaphragm    -   121 Hole    -   131 Valve chamber    -   133, 133 a Second flow path    -   134 Communication hole    -   134 a Cavity    -   136 Narrowing part    -   138 Valve seat    -   152 Seal member    -   160 Check valve    -   170 Exhaust valve    -   190 Case    -   191 First plate    -   191 a, 191 b, 191 c Groove    -   191 d Opening    -   191 e Wall portion    -   192 Second plate    -   192 a Protrusion    -   193, 193 a, 193 b, 193 c Exhaust path-forming plate    -   193 a Protrusion    -   195 Frame member

1. A valve comprising: a first plate having at least one first venthole; a second plate positioned to face a main surface of the firstplate and having a second vent hole; a valve chamber positioned betweenthe first plate and the second plate; a valve body positioned betweenthe first plate and the second plate and having a third vent hole, thevalve body causing the first vent hole and the second vent hole not tobe in communication with each other when a periphery of the third venthole is in contact with the first plate or the second plate, and causingthe first vent hole and the second vent hole to be in communication witheach other when the periphery of the third vent hole is separated fromthe first plate and the second plate; an exhaust path-forming platepositioned between the second plate and the valve body, forming a firstflow path between the exhaust path-forming plate and the valve body,forming at least one second flow path between the exhaust path-formingplate and the second plate, and having a fourth vent hole through whichthe first flow path is in communication with the second flow path; andat least one fifth vent hole in the second plate, wherein the first flowpath establishes communication between the second vent hole and thefourth vent hole, and the second flow path establishes communicationbetween the fourth vent hole and the fifth vent hole, the valve bodycauses the first flow path and the second flow path not to be incommunication with each other when the valve body is in contact with aperiphery of the fourth vent hole, and the valve body causes the firstflow path and the second flow path to be in communication with eachother when the valve body is separated from the periphery of the fourthvent hole, a minimum cross-sectional area of the second flow path or across-sectional area of the fifth vent hole is smaller than across-sectional area of an opening of the fourth vent hole, and adirection in which the fourth vent hole extends differs from a directionin which the second flow path extends.
 2. The valve according to claim1, wherein the second plate is a part of a case accommodating the valve.3. A gas control device comprising: the valve according to claim 1; apump connected to the valve chamber; and a container connected to thefirst flow path.